Due to their low specific weight and their mechanical properties, components made of titanium aluminides or TiAl alloys are of interest for use in gas turbines, in particular aircraft turbines.
Titanium aluminides or TiAl alloys are understood to be alloys which include titanium and aluminum as the main constituents, so that aluminum and titanium are the components present in the highest proportions in the chemical composition thereof. Moreover, TiAl alloys are characterized by the formation of intermetallic phases, such as γ-TiAl or α2-Ti3Al, which give the material good strength properties.
However, TiAl alloys are not easy to process, and the microstructures of TiAl materials have to be precisely adjusted to obtain the desired mechanical properties.
DE 10 2011 110 740 B4, for example, describes a method for producing forged TiAl components, where a two-stage heat treatment is performed subsequent to forging in order to obtain the desired microstructure. Documents DE 10 2015 103 422 B3 and EP 2 386 663 A1 also disclose methods for producing components from TiAl alloys.
European Laid-Open Application EP 2 386 663 A1 already addresses the problem that TiAl alloys can often have an inhomogeneous microstructure and, therefore, the properties of the TiAl material also exhibit inhomogeneities. However, this is undesirable when using the TiAl alloys in turbomachines such as aircraft engines. In this regard, EP 2 386 663 A1 proposes to subject the deformed TiAl material to a heat treatment to achieve recrystallization. However, this does not completely solve the problem of the formation of inhomogeneous microstructures.